Composite shaft

Abstract

A turbine shaft may be used to remove a heat load from pliant bearings without requiring the use of a process fluid for cooling the turbine shaft. The turbine shaft comprises a heat conductive sleeve disposed between an outer surface of a tie rod shaft and an inner surface of a bearing journal; the heat conductive sleeve having a sleeve inner surface separated from a sleeve outer surface by a sleeve thickness; the heat conductive sleeve having a first end separated from a second end longitudinally about a center axis; the sleeve outer surface being in physical contact with the inner surface of the bearing journal; and the heat conductive sleeve having a thermal conductivity that is greater than a thermal conductivity of the bearing journal.

1. A turbine shaft comprising:
 a solid heat conductive element disposed radially about a center axis and within an inner surface of a bearing journal; 
 said solid heat conductive element having a solid heat conductive element outer surface in physical contact with said inner surface of said bearing journal; 
 said solid heat conductive element having a solid heat conductive element first end separated longitudinally from a solid heat conductive element second end about said center axis; 
 said solid heat conductive element having a thermal conductivity that is greater than a thermal conductivity of said bearing journal. 
 
   
   
     2. The turbine shaft of  claim 1 , wherein an insulator is disposed between said solid heat conductive element first end and a turbine wheel. 
   
   
     3. The turbine shaft of  claim 2 , wherein said insulator is a gas or a partial vacuum. 
   
   
     4. The turbine shaft of  claim 1 , wherein said solid heat conductive element has a thermal conductivity of at least about 50 watts per meter degree Kelvin. 
   
   
     5. The turbine shaft of  claim 1 , wherein said solid heat conductive element has a thermal conductivity of at least about 390 watts per meter degree Kelvin. 
   
   
     6. The turbine shaft of  claim 1 , wherein said solid heat conductive element comprises at least one of copper, aluminum, silver, a ceramic material, a carbon graphite material, and an impregnated carbon graphite material.